WIP: Propagate SurfaceID up window tree hierarchy

services/ui/ws/server_window_delegate.h

Index: services/ui/ws/server_window_delegate.h
diff --git a/services/ui/ws/server_window_delegate.h b/services/ui/ws/server_window_delegate.h
index 1835727d35d010d600a207c372d5c2603563d527..6046a8106a35a5d21a308a90083ebca305a94c0e 100644
--- a/services/ui/ws/server_window_delegate.h
+++ b/services/ui/ws/server_window_delegate.h
@@ -12,7 +12,9 @@
 
 namespace ui {
 
-class SurfacesState;
+namespace surfaces {
+class DisplayCompositor;
+}
 
 namespace ws {
 
@@ -22,7 +24,7 @@ struct WindowId;
 
 class ServerWindowDelegate {
  public:
-  virtual SurfacesState* GetSurfacesState() = 0;
+  virtual surfaces::DisplayCompositor* GetDisplayCompositor() = 0;
 
   virtual void OnScheduleWindowPaint(ServerWindow* window) = 0;